Portland-Limestone Cements: History, Performance, and Specifications
Paul D. Tennis, Ph.D. Portland Cement Association Today’s Objectives What is a portland-limestone blended cement History Environmental performance Concrete performance Changes to the specifications Portland-Limestone Cement
Why? Provides an option to implement proven technology to obtain desired performance and improve sustainability of concrete
What is Portland-Limestone Cement?
ASTM C595 and AASHTO M 240 Blended Cement Type IL or Type IT with limestone 5% to 15% limestone
HISTORY History of Limestone in Cements
1965 Cement with 20% limestone in Germany for specialty applications 1979 French cement standards allows limestone additions. 1983 CSA A5 allows up to 5% limestone in portland cement 1990 15±5% limestone blended cements routinely used in Germany 1992 UK specs allows up to 20% in limestone cement 2000 EN 197-1 allows 5% MAC (typ. limestone) in all 27 common cements, History of Limestone in Cements
2000 EN 197-1 creates CEM II/A-L (6-20%) and CEM II/B-L (21-35%) 2004 ASTM C150 allows 5% in Types I-V 2006 CSA A3001 allows 5% in other Types than GU 2007 AASHTO M85 allows 5% in Types I-V 2008 CSA A3001 includes PLC containing 5%-15% limestone European Cement Use 100 1.7 2.1 1.8 2.1 2.2 1.5 1.9 6.1 3.4 2.9 1.8 Others 5 3.2 5.0 5.7 9.5 5.4 CEM V - Composite Cement 90 4.0 6.5 5.5 5.1 5.6 CEM IV - Pozzolanic 5.6 4.8 CEM III - Blast furnace slag 80 14.5 12.5 16.8 9.6 14.3 CEM II - Portland-composite 16.8 CEM II - Portland-limestone 70 CEM II - Portland-fly ash CEM II - Portland-pozzolana 24.0 60 18.9 24.6 15.0 24.5 31.4 CEM II - Portland-slag CEM I - Portland 50 5.4 6.2 7.0 5.7 3.7 2.9 6.9 40 2.1 2.7 4.8 5.4 1.2 7.4 4.2 6.8 5.9 1.4 30 4.5
Cement Types (%) in Europe Types Cement 20 35.4 34.2 33.7 32.1 31.6 27.5 10
0 1999 2000 2001 2002 2003 2004 Cembureau data ENVIRONMENTAL BENEFITS Barcelo, Kline and Walenta, 2012 from Ashby (2009) Energy to Produce Cement Environmental Benefits 10% 15% Energy Reduction* Fuel (million BTU) 443,000 664,000 Electricity (kWh) 6,970,000 10,440,000
Emissions Reduction*
SO2 (lb) 581,000 870,000
NOX (lb) 580,000 870,000 CO (lb) 104,000 155,000
CO2 (ton) 189,000 283,000 Total hydrocarbon, THC (lb) 14,300 21,400 * Per million tons cement Environmental Benefits
Portland cement 1.0 Portland-limestone cement
0.8
0.6 /kg cement 2 0.4 kg CO
0.2
0.0 Plant 1 Plant 2 Plant 3 Why 15%? How Limestone Works
Particle packing Improved particle size distribution Nucleation Surfaces for precipitation Chemical reactions Only a small amount, but… How Limestone Works
Particle packing Improved particle size distribution Nucleation Surfaces for precipitation Chemical reactions Only a small amount, but… How Limestone Works
Particle packing Improved particle size distribution Nucleation Surfaces for precipitation Chemical reactions Only a small amount, but… ASTM AND AASHTO UPDATES Process JAAHTG reviewed concept January 2010 Technical information from Europe and Canada considered Presented concept to AASHTO TS3a and ASTM C01.10 summer 2010 TS3a ballot in 2011; SOM ballot December 2011. C01.10 ballot April 2011; C01 ballot October 2011 Ballot items passed; 2012 AASHTO M240 and ASTM C595 published AASHTO M240 & ASTM C595 Requirements Type IL—Portland-limestone blended cement Example: Type IL(10) = 10% limestone Type IT—Ternary blended cement with limestone Example 1: Type IT(L12)(P10) = 12% limestone and 10% pozzolan Example 2: Type IT(S15)(L10) = 15% slag and 10% limestone Limestone content 5% to 15%
AASHTO M240 & ASTM C595 Requirements
Same physical requirement as existing C595/M240 cement types Chemical requirements – sulfate content, LOI Sulfate resistance – no MS or HS in initial specifications
Limestone characteristics– CaCO3, MBI, TOC
IP IS (<70) IP(LH), IL IL(LH), IS (< 70) (MS), IS (< 70) (HS), IT(P≥S) IT(P≥S)(LH) IT(P IP IP(LH), IS (<70) IL(LH), IL IS (< 70) (MS), IS (< 70) (HS), IT(P≥S)(LH) IT(P≥S) IT(P Water req...... 64 max % Drying shrinkage, ...... 0.15 max, % Mortar expansion, max, %: 14 days 0.020 0.020 0.020 0.020 0.020 8 weeks 0.060 0.060 0.060 0.060 0.060 Sulfate resistance, expansion, max, %: at 180 d 0.10 0.05 at 1 year 0.10 Chemical Requirements for Blended Cements IS(< 70), I P, IL IS(≥70), Cement Type IT(P SO3, max, % 3.0 4.0 4.0 3.0 S2-, max, % 2.0 2.0 ...... Insol. res. max, %C 1.0 1.0 ...... LOI, max, % 3.0D 4.0D 5.0D 10.0 C Insol res max does not apply to ternary blended cements. D For ternary blended cements with limestone LOI max = 10%. Requirements for Limestone for Use in Blended Cements Test Method Limit CaCO3 content C114/T105 Min. 70% Methylene blue index See Annex A2 Max. 1.2 g/100g Total organic carbon See Annex A3 Max. 0.5% Limestone Testing Summary Portland-limestone blended cements 5% to 15% limestone History of use: Europe, Canada, US Mechanisms An option to make greener concrete Additional information [email protected] Portland Limestone Blended Cement in ASTMThank C595 you! and AASHTO M240 Presented to ASTM C01.10 December 2010 North American PLC Pavements Field Applications in Canada, Utah and Colorado Todd Laker, Holcim (US) Inc. Brooke Smartz, Holcim (US) Inc. 1 Portland-Limestone Cement Paving Projects . +125 miles of concrete paving in Colorado and Utah Performance and Environmental Benefit 2 CDOT and UDOT Specifications . Allow portland-limestone cements that meet ASTM C1157 performance specification for GU (General Use), MS (Moderate Sulfate Resistance) and HS (High Sulfate Resistance) . Supplementary cementitious materials required for applications that require resistance for sulfate attack and/or alkali silica reactivity for both ASTM C150 and ASTM C1157 cements 3 Verifying Portland Limestone Cement Durability . Holcim ASTM C595 (Type IL) or ASTM C1157 cements are tested for durability performance. Tests generally include: Fresh & Hardened concrete properties - Requirements are met through concrete mix design – ASTM Sulfate Resistance - ASTM C1012 Alkali-Silica Reactivity - ASTM C1260/1567 Freeze Thaw & Deicer Scaling Resistance - ASTM C666 & C672 Shrinkage – ASTM C157 Chloride Ion Penetration – ASTM C1202 4 How do Portland-Limestone Cements compare? ASTM Designation PLC vs C150 PLC vs C150 PLC vs C150 PLC vs C150 PLC vs C150 Strength 28D (C39) Equal Better Better Better Equal Sulfate (C1012) Equal Equal Equal Equal Equal ASR (C1260/C1567) Better Equal Equal Equal Equal Freeze-Thaw (C666) Equal Equal Equal Equal Equal Deicer Scaling Equal Equal Equal Equal Equal (C672) Shrinkage (C157) Equal Equal Equal Equal Equal Permeability Slightly Better Equal Equal Equal Equal (C1202) 5 How do Portland-Limestone cements perform in the field? . Equal or improved to C150 cements Strength Set time Water demand Compatibility with fly ash Compatibility with admixtures . Improved finishability . Lower environmental impact 6 Devil’s Slide, Utah Cements . Type V clinker C3A <5% . ASTM C150 Type II/V High sulfate resistance - C3A <5% <5% limestone per ASTM C150 Naeq <0.60% . ASTM C1157 Type GU/MS General use/Moderate sulfate resistance - ASTM C1012, sulfate performance test 10% limestone 7 Utah PLC Case Studies 8 Lost Creek Road Morgan, Utah . Rural County Road Constructed 2009 Major Truck Traffic Construction Limitations Mountain weather issues . Performance System 10% Limestone Cement 20% Class F fly ash . Compressive strength design 4000 psi, average 5120 psi . Flexural strength design 650 psi, average 720 psi 9 10 104th South, Salt Lake City, Utah . Pooled Fund Ternary Study (2009) University of Utah* (Tikalsky) 10% Limestone Cement 25% Class F Fly ash . Single days production . Control Section Strength* Compressive 4454 psi 28Day . Actual Test Section Strength* Compressive 5396 psi 28Day 11 SR 201, Salt Lake City, Utah . Eastbound lanes paved August 2009 with ASTM C150 Type II/V . Westbound lanes paved October 2009 with ASTM C1157 10% portland-limestone cement Both mixes contained 25% Class F fly ash . Eastbound Strength Compressive ~5000 psi Average Concrete Temp ~70 F . Westbound Strength Compressive ~4500 psi Average Concrete Temp ~50 F 12 UTA FrontRunner South Salt Lake City to Provo, Utah 13 UTA FrontRunner South Salt Lake City to Provo, Utah . Keystone Concrete Masonry Units (CMU) 10% Limestone Cement 15% Class F Fly ash . 350,000 square feet or retaining wall . Block on the project Averages: 28 day Compressive Strength 6,500 psi Absorption of 5.3% . 37 Foot Tall Retaining Wall 55 block courses above grade 10 block courses below grade 14 Portland, Colorado Cements . Type II clinker C3A <8% . ASTM C150 Type I/II General use/Moderate sulfate resistance - C3A <8% <5% limestone per ASTM C150 Naeq >0.70% . ASTM C595 Type IP(HS) 25% Class F fly ash . ASTM C1157 Type GU/MS General use/Moderate sulfate resistance - ASTM C1012, sulfate performance test 10% limestone 15 Colorado PLC Case Studies Performance & Lower Environmental Impact 16 City of Denver Concrete Paving 40th & Havana and Holly Street 17 City of Denver Concrete Paving . Aligns with Denver Greenprint Program . 40th & Havana - side by side comparison of ASTM C150 I/II and ASTM C1157 GU cements (2007) 20% Class C fly ash No noticeable performance differences Winter construction . Holly Street - Ready-mix concrete supply (2008) 25% Class C fly ash 18 City of Denver Concrete Paving Central Park Boulevard 19 DIA Pena Boulevard 20 US HW 287 Near Lamar, CO 21 US HW 287 Near Lamar, CO . 7 Miles PCCP (2008) Hot dry summer construction . Ports to Plains US Highway route Heavy truck traffic . 20% Class F fly ash . 695 psi average 28-day flexural strength . Contractor received quality incentive per CDOT specifications . Used in concrete paving on a regular basis in Colorado 22 US HW I-25 Near Castle Rock, CO 23 US HW I-25 Near Castle Rock, CO . 5 Miles PCCP (2008) . Major Interstate Highway . 20% Class F fly ash . 720 psi average 28-day flexural strength . Contractor received quality incentive per CDOT specifications . Used in concrete paving on a regular basis in Colorado 24 Canada PLC Case Studies . http://www.mto.gov.on.ca/english/engineering/ new-cement.shtml 25 Keep in mind… . No cement or scm’s can offset low quality concrete . Durable concrete depends on: Appropriate mixture proportions Lower w/cm Air entrainment in F/T conditions Proper placement Curing Maintenance . When good practices are followed, concrete will attain its expected service life 26 Summary . Projects demonstrate concrete made with portland-limestone cements are readily constructible and can easily achieve specified strength requirements. . Durability testing shows similar or improved performance to ASTM C150 cements . Portland-limestone cements can provide performance and lower environmental impact 27 Over 125 miles of paving in Colorado and Utah 28 Thank You! Any Questions? Todd Laker, LEED AP Holcim (US) Inc. [email protected] or 801-829-2178 Brooke Smartz, LEED AP Holcim (US) Inc. [email protected] or 303-716-5288 29 Performance of PLC Concrete: Fresh, Hardened and Durability Properties Michael Thomas University of New Brunswick TRB Webinar: Portland Limestone Cement (PLC) - A Technology to Improve the Sustainability of Concrete Pavements – November 13, 2012 Portland Cement (PC) Manufacture Calcination: CaCO3 → CaO + CO2 CaCO3 (limestone) ~ 0.50 ton CO2 per 2SiO2•Al2O3 (clay, shale) 1.0 ton of clinker Fe2O3 (iron oxide) CO2 SiO2 (silica sand) Fuel: ~ 0.25 to 0.65 ton CO2 per ton of clinker Heat Kiln 3CaO•SiO2 CaO•SO3•2H2O 2CaO•SiO2 Gypsum + Clinker 3CaO•Al2O3 4CaO•Al2O3•Fe2O3 Finished interground cement Cement production accounts for approximately 7% to 8% of CO2 globally (Mehta, 1998) … … and approximately 2.8% of CO2 emissions in Canada (Neitzert, 1997) 60% Calcination: CaCO3 → CaO + CO2 ↑ (gas) Energy: C + O2 → CO2 ↑ (gas) 40% www.cement.ca Portland Limestone Cement (PLC) Manufacture Calcination: CaCO → CaO + CO CaCO3 (limestone) 3 2 ~ 0.50 ton CO2 per 2SiO2•Al2O3 (clay, shale) 1.0 ton of clinker Fe2O3 (iron oxide) CO2 SiO2 (silica sand) Fuel: ~ 0.25 to 0.65 ton CO2 per ton of clinker Heat Kiln 3CaO•SiO2 CaCO3 CaSO4•2H2O 2CaO•SiO2 Limestone + Gypsum + Clinker 3CaO•Al2O3 4CaO•Al2O3•Fe2O3 Finished interground cement Tests carried out with Canadian materials: 2007-10 • Portland-limestone cements (PLC) were produced in different grinding circuits with various clinkers (C3A from 4.5 to 12%) and limestones. • Amount of limestone varied between 3 and 19% (to keep within limits, the real CSA PLC max. will be ~13%). • Standard mortar tests and chemical analyses were performed on the different PLCs. • Concrete with various w/cm ratio’s 0.35 to 0.80 were produced. The cement contents in the mixed varied between 225 and 420 kg/m3 • Concrete tests with different PLC’s (10 to 22 %LS) and various amounts of slag (15, 25, 30%) and fly ash (20%) were performed • Slump, slump retention and air were measured • Durability tests were performed, e.g. RCP, freeze/thaw, salt scaling, shrinkage, sulfate resistance, and ASR • Testing conducted by cement companies and universities • Field trials Durability of PLC Concrete: Canadian Studies • PLC with up to 15% limestone - equivalent performance as portland cement from the same clinker • Equivalent performance achieved by increasing Blaine by 100 to 120 m2/kg • Performance in this study was evaluated based on: • Strength • Resistance to freeze- thaw and de-icer salt scaling • “Chloride permeability” and chloride diffusion. • Alkali-silica reaction CSA A3001-08 Types of Hydraulic Cement Blended PLC – 2010 Amendment GULb New in 2008 → MSLb MHLb HELb LHLb HSLb PLC is produced to provide equivalent performance to PC in Canada So requirements for Type GUL (up to 15% limestone) same as Type GU (< 5%) CSA A23-09 Use of Portland Cement in Concrete • Portland limestone cement is permitted for use in all classes of concrete except for sulfate exposure classes (S-1, S-2, S-3) Beneficial Effects of Limestone Addition • Limestone (primarily CaCO3) chemically reacts with C3A to form carboaluminates—at least at replacements of 5-10% hydration C3 A + CC + xH →C3 A⋅CC ⋅ H x Limestone is not totally inert ! Tri-calcium Interground Calcium monocarboaluminate aluminate limestone in clinker (a.k.a. monocarbonate) • Finer limestone particles fill the voids between clinker particles improving the grain packing of cement • Fine limestone particles as nucleation sites for hydration products at early hydration ages accelerating the hydration and consequently improving the early strength Effect of Fineness on Performance 50 W/CM = 0.49 - 0.51 6000 (psi)Strength Compressive 40 1 day 7 days 30 28 days 4000 56 days 20 2000 Compressive Compressive Strength(MPa) 10 0 0 380 450 500 580 PC PLC with 12% Limestone Blaine (m2/kg)) Testing in Canada indicates that the Blaine of PLC needs to be increased by approx 100 – 120 m2/kg compared with PC to obtain equivalent performance Fineness PLC vs. PC 100 80 PLC 60 PC 40 Passing (%) 20 To achieve equivalent performance PLC is ground to a higher fineness 0 1 10 100 1000 Particle Size (μm) Fineness in PLC: Clinker vs. Limestone 100 80 60 D50 Limestone: 7 to 10 μm D50 Clinker: 15 μm 40 Passing (%) 20 Limestone fineness in the interground product is significantly finer than the clinker fraction 0 1 10 100 1000 Particle Size (μm) Field Trials Brookfield Cement Plant, NS Exshaw Cement Plant, AB Gatineau Concrete Plant, QC Gatineau, Quebec Exshaw, Alberta Brookfield, Nova Scotia October 2008 September 2009 October 2009 Cementitious Materials used in Field Trials CSA Type Description ASTM Equivalent GU “General Use” portland cement, PC C 150 Type I GUL “General Use” portland limestone cement, PLC C 1157 Type GU GUb-15S “General Use” blended hydraulic cement C 595 Type IS GULb-15S “General Use” blended limestone cement C 1157 Type GU F Fly ash < 8% CaO C 618 Class F CI Fly ash 8-20% CaO C 618 Class F S Ground granulated blastfurnace slag C 989 PLC Trial Pour at Gatineau Ready-Mixed Concrete Plant – October 6, 2008 Objective: • Field test performance of PLC concrete with various levels of SCM in an exterior flatwork application. • Control sections with Type GU + SCM Eight Concrete Mixes: Cement SCM Replacement Level (%) 0 25 40 50 Type GU (PC) X X X X Type GUL (PLC) X X X X Cementing Materials: • Type GU with 3.5% limestone (PC) • Type GUL with 12% Limestone (PLC) • Blended SCM = 2/3 Slag + 1/3 Fly Ash Exshaw Cement Plant, Alberta • Sept 2009 • Paving, Curbs & pumped concrete • PC & PLC cements • 15, 25 & 30% fly ash Brookfield Cement Plant, Nova Scotia •Oct 2009 •Paving •Blended PC & PLC cements containing 15% slag •15 & 20% fly ash CSA Type Abbrev. Gypsum Limestone Slag Clinker Target Blaine (%) (%) (%) (%) (m2/kg) Type GU PC 5 4 0 91 380 Type GUb PC-Slag 5 0 15 80 450 Type GULb PLC-Slag 5 12 15 68 500 PC, PC-Slag & PLC-Slag compared in laboratory mixes Only PC-Slag & PLC-Slag compared in field mixes Testing of Concrete Produced for Laboratory Trials Test Method Slump C 143 Air (plastic concrete) C 231 Set time C 403 Hardened air voids C 457 Compressive strength C 39 “Rapid chloride permeability” C 1202 Freeze-thaw resistance C 666 (Proc. A) Salt-scaling resistance C 672 Diffusion coefficient C 1556 PLC Trial Pour at Gatineau Ready-Mixed Concrete Plant – October 6, 2008 Fresh concrete properties: • Slump • Air • Temperature • Density Hardened concrete properties on site-cast specimens: • Strength • RCPT • Hardened Air-Void Parameters • Freeze-thaw (ASTM C 666: Proc. A) • Salt Scaling (ASTM C 672 & BNQ Method) Properties of 35-Day-Old Cores: • Strength • RCPT • Chloride diffusion coefficient Brookfield Trial: Type PC-Slag versus Type PLC-Slag Mix Proportions (lb/yd3) No Fly Ash 15% Fly Ash 20% Fly Ash PC-Slag PLC-Slag PC-Slag PLC-Slag PC-Slag PLC-Slag PC-Slag 653 - 545 - 513 - PLC-Slag - 384 - 545 - 515 Fly Ash 0 0 95 97 128 128 Water 272 283 277 275 280 275 W/CM 0.42 0.44 0.43 0.43 0.44 0.43 Brookfield Trial: Type PC-Slag versus Type PLC-Slag Fresh Concrete Properties No Fly Ash 15% Fly Ash 20% Fly Ash PC-Slag PLC-Slag PC-Slag PLC-Slag PC-Slag PLC-Slag Air (%) 5.8 6.6 6.1 6.2 6.6 6.5 Slump (mm) 3 2¼ 3¼ 2½ 2½ 3 PLC Trial Pour at Gatineau Ready-Mixed Concrete Plant – October 6, 2008 • Results published in Concrete International (Jan 2010) • SCM had significant impact on properties • No consistent difference between the durability results for PLC versus PC at the same level of SCM • Mix with PLC-50% SCM contained just 42% clinker by mass of cementing material. Compare with mix with PC only – 92% clinker 3 • CO2 reduced by 1 ton per 8-yd truck through combined use of limestone and SCM PLC Trial Pour at Gatineau – RCPT Results 4000 PC at 28 days 3000 PLC at 28 days PC at 56 days PLC at 56 days 2000 1000 28d Charge Passed Charge (Coulombs) 56d 0 0 10 20 30 40 50 60 SCM Replacement Level (%) PLC Trial Pour at Gatineau – Results of Tests on Cores taken at 35 Days RCPT Results Charge Passed in 6 Hours (Coulombs Cement 0% SCM 25% SCM 40% SCM 50% SCM PC 2395 1410 570 491 PLC 2345 1308 617 520 Chloride Diffusion Coefficients Charge Passed in 6 Hours (Coulombs Cement 0% SCM 25% SCM 40% SCM 50% SCM PC 15.0 3.77 1.51 1.25 PLC 11.9 2.91 1.22 1.81 PLC Trial Pour at Gatineau - Chloride Profiles for Cores taken at 35 Days and Immersed in NaCl for 42 Days 1.2 PC - 0% SCM 1.0 PLC - 0% SCM PC - 25% SCM 0.8 PLC - 25% SCM 0.6 PC - 50% SCM PLC - 50% SCM 0.4 0.2 Chloride (% (% Chloride by mass ofconcrete) 0.0 0 5 10 15 Depth (mm) PLC Trial Pour at Gatineau – Scaling Test Results 600 ) 2 BNQ Test Method 497 380 400 PC PLC 273 200 142 114 127 106 ScaledMass Loss (g/m 39 0 600 ) 2 ASTM C 672 400 400 PC 320 PLC 230 200 80 50 ScaledMass Loss (g/m 40 10 30 0 0% SCM 25% SCM 40% SCM 50% SCM PLC Trial Pour at Exshaw – Cylinder Strengths Compressive Strength (MPa) Strength Compressive 6000 40 Age (days) 1 7 30 4000 28 56 20 2000 Compressive Compressive Strength(psi) 10 0 0 GU GUL GU GUL GU GUL GU GUL Cement Type 0 15 25 30 Fly Ash (%) 3 373 kg/m clinker 238 kg/m3 clinker 3 (622 lb/yd ) (397 lb/yd3) Initial Trials at Brookfield – Type GU versus Type GUb – with & without Fly Ash 50 7500 1 day 7 days 40 6000 (psi) Strength Compressive 28 days 30 4500 20 3000 10 1500 Compressive Compressive Strength(MPa) 0 0 GU-0FA GUb-0FA GU-20FA GUb-20FA Cement Type Laboratory Mixes at Brookfield – Type GU, Type GUb & Type GULb 50 7500 8 1200 GU GU GUb GUb 40 GULb 6000 (psi) Strength Compressive GULb 6 900 (psi) Strength F lexural 30 4500 4 600 20 3000 Flexural Strength (MPa) Flexural 2 300 Compressive Compressive Strength(MPa) 10 1500 0 0 0 0 7 days 28 days 7 days 28 days Age (days) Age (days) Gypsum (%) Limestone (%) Slag (%) Clinker (%) Target Blaine (m2/kg) Type GU 5 4 0 91 380 Type GUb 5 0 15 80 450 Type GULb 5 12 15 68 500 Field Trials at Brookfield – Compressive Strength 0% Fly Ash 15% Fly Ash 20% Fly Ash 50 w/cm = 0.417 Air = 5.8% 40 6000 Strength (psi) Strength 30 4000 w/cm = 0.443 20 Air = 6.6% Strength (MPa) 2000 PC - 0 PC - 15 PC - 20 10 PLC - 0 PLC -15 PLC -20 0 0 3 7 28 90 365 3 7 28 90 365 3 7 28 90 365 Age (days) Age (days) Age (days) Field Trials at Brookfield & Exshaw – Salt Scaling Typical limits in Canadian Specs: 800 to 1000 g/m2 300 8 GU or GUb 250 GUL or GULb Mass Loss (g/m Loss Mass ) 6 2 200 150 4 2 100 ) 2 Mass Loss (oz/yd 50 0 0 Alberta - Concrete with GU or GUL Nova Scotia - Concrete with GUb or GULb Field Trials at Brookfield & Exshaw – RCPT 5000 Concrete tested at 100 days GU or GUb 4000 GUL or GULb 3000 Concrete tested at 56 days 2000 1000 Charge Passed Charge (Coulombs) 0 Alberta - Concrete with GU or GUL Nova Scotia - Concrete with GUb or GULb Field Trials at Brookfield – Chloride Diffusion Coefficients 1.0 0.8 GUb-0FA GUbL-0FA 0.6 GUb-20FA GUbL-20FA 0.4 Chlroide Content Chlroide (%) 0.2 No fly ash 20% fly ash 0.0 0 5 10 15 20 Depth (mm) No Fly Ash 20% Fly Ash x C = C GUb GULb GUb GULb x 0 4Da ⋅t -12 2 Da (x 10 m /s) 6.1 6.4 3.9 3.4 Brookfield Cement Plant, Nova Scotia Gypsum Limestone Slag Clinker Target Blaine (%) (%) (%) (%) (m2/kg) Type GU 5 4 0 91 380 Type GUb 5 0 15 80 450 Type GULb 5 12 15 68 500 • Type GULb contains 23% less clinker than Type GU Type GU Cement Type GULb Cement Gypsum Limestone 91%92% Clinker Gypsum 68%Clinker Limestone Slag Approx 23% reduction in clinker (& CO2 emissions) Mixes used in Gatineau Field Trial Concrete Mix Composition of Binder (%) Gypsum Limestone SCM Clinker GU + 0% SCM 5 4 0 91 GUL + 50% SCM 2.5 6 50 41.5 • Mix with GUL + 50% SCM contains approximately 50% less clinker in the binder than mix with straight Type GU cement Type GU Cement Type GULb Cement Gypsum Limestone 41.5% Clinker 91%92% Clinker Gypsum Limestone SCM Approx 50% reduction in clinker (& CO2 emissions) Gatineau Field Trial Clinker Contents of Mixes used for Paving Trials (355 kg/m3 cementitious material) Clinker in Clinker in concrete Clinker in concrete with Concrete Mix Cement (%) without SCM (kg/m3) 50% SCM(kg/m3) GU + 0% SCM 91 323 162 GUL + 50% SCM 83 295 147 3 3 • 176 kg/m reduction in cement clinker (= 176 kg/m reduction in CO2) by combined use of Type GUL cement plus SCM compared with Type GU 3 • CO2 reduced by almost 1½ tonne per 8-m truck 3 3 • 293 lb/yd reduction in cement clinker (= 293 lb/yd reduction in CO2) by combined use of Type GUL cement plus SCM compared with Type GU 3 • CO2 reduced by almost 1½ ton per 10-yd truck Overall Summary • Portland-limestone cement (PLC) with 12% limestone, when optimized for equal strength, can provide equivalent performance to Portland cement (Type PC) • Blended portland-limestone cement with 12% limestone and 15% slag also provided equivalent performance to PC with 23% less clinker • PLC performs well with (further) additions of SCM at the ready- mixed concrete plant (providing further opportunities to reduce CO2 emissions). • Using a combination of PLC or blended PLC together with (further) SCM additions at the concrete plant provides the opportunity to reduce the clinker content of paving mixes by up to 50%. Such reductions can translate to CO2 reductions of the order of 1 to 1½ tons per concrete truck!